Science Buddies: "Ask an Expert"

For my science fair I will be conducting an experiment similar to the mpemba effect project on this website. Now what are some things i can add or change to the experiment to make it good enough to go to the next level. I read the ideas in the make it your own tab but none of those really makes the experiment any better. Please respond asap and thanks.

doomlord,

This is an interesting phenomenon and a tricky experiment to conduct. As you see in the write up, there is great debate on what conditions play a role in allowing the effect to take place. Perhaps you could try to isolate some of the conditions and test the sensitivity of the effect to those conditions. This is slightly different from testing the effect itself, as it assumes the effect is going to occur and requires you to design an experiment where you can consistently see the effect and then change your one condition to test the sensitivity to that change. For example you could start with distilled water as your control and then add impurities in increasing amounts in successive runs until you no longer see the effect. This would require very careful management of your control variables. There are other conditions that could be tested in this way. A good bit of research will likely reveal some others.

hi i have another question. it says in the report on the mpemba effect by jeng that the mpemba effect disagrees with the modern understanding of heat. how exactly does it do so?

doomLord,
Sorry for the delay in responding. There is disagreement on the mechanism that allows the warmer water to freeze first. As something cools down, it looses energy. Logic says that if it starts out warmer it has a higher thermal energy level and it would take it longer to dump that energy to the cold environment of the freezer. One hypothesis is that by boiling the water, the molecules loose more energy in collisions with the walls of the container facilitating heat transfer at those surfaces faster than cooler water. However, this hasn't been proven to my knowledge. There are other hypothesis out there, I invite you to do a search for your own project background research and see which ones match your observations.